Who is Alfred
Wegener?
What is the Theory
of Continental Drift?
Wegener’s lines of evidence for Continental Drift
included:
1)
2)
3)
4)
The main problem with
the Continental Drift hypothesis was…
Who is Harry Hess?
What did Hess use to
obtain information about the morphology of the sea floor?
Where are the world’s longest mountain chains located?
The Sea Floor Spreading Hypothesis stated:
1)
2)
3)
What did Sea-floor
Spreading offer that that Continental Drift did not?
The study of the
earth’s magnetic field as preserved by magnetic minerals in rocks is called:
____________________
The horizontal angle
made between Magnetic North and True North is
called:___________________________-
The angle made between
the earth’s magnetic field and horizontal is called:
_______________________________
How does magnetic inclination
vary with latitude?
(figure 2.9 &
2.10))
What are Apparent
Polar Wandering Curves and how did they form?
(figure 2.11)
What are magnetic reversals?
(figure 2.13)
The Geomagnetic Time Scale
(figure 2.14)
What are “magnetic
stripes”?
(figure 2.15 &
2.16)
How do they form?
(figure 2.17)
How did the Glomar Challenger drilling ship test the sea-floor spreading
hypothesis?
How do magnetic anomalies date the age of the ocean?
Did the North Atlantic or South Atlantic begin to form first, and how do
you know?
What do earthquakes
have to do with the development of the Theory of Plate Tectonics?
Plate Tectonics: the
new Ruling Paradigm:
Fundamental concepts
include:
1) The outermost shell
of the earth consists of a strong, rigid lithosphere, composed of the
crust and upper mantle
2) The lithosphere
rides over a weak, partly melted portion of the mantle, the asthenosphere.
(fig. 1.14)
3) The lithosphere is
broken into a series of large, rigid plates that move relative to one another,
driven by convection in the mantle.
(fig. 2.31)
4) Most of the
deformation and volcanic activity on the earth is concentrated at the
boundaries between adjacent plates.
(fig. 2.19)
In fact, the global
distribution of earthquake epicenters is used to define the boundaries of the
earth’s plates!
Divergent Plate Boundaries and rifting of the continents:
__________________ forces acting on lithospheric plates splits landmasses into two or more smaller segments along a continental rift.
e.g. East African rift valleys and the Rhine Valley in northern Europe
(fig. 2.21)
Divergent Plate
Boundaries:
Most are
located along the crests of oceanic ridges and rises where new oceanic
lithosphere is formed.
The topographic expression of the ridge/rise sysem is controlled by the __________________________.
(fig. 2.2)
(see also the GEODE
disk in the back of your textbook)
What surprising feature was found by geologists exploring the mid-ocean
spreading vents?
Types of Convergent Plate Boundaries: (fig. 2.22)
1) _____________________
2) ________________________
3) ___________________________
_____________________________ Convergent Boundaries: (fig. 2.22B)
* Denser oceanic slab sinks (is subducted) into the asthenosphere at
an ___________________
* Partial melting along the descending plate generates
____________.
*
Rising
magma forms an arcuate volcanic chain called a ___________________
e.g. ______________, _______________, ____________
_____________________________ Convergent Boundaries: (fig. 2.22A)
* Denser oceanic slab is subducted beneath an adjacent
__________________.
* Partial melting of the subducted slab at depth generates
magma
*
Resulting
volcanic mountain chain is called a __________________________
e.g. __________ and _________________
_____________________________ Convergent Boundaries: (fig. 2.22C)
* Continued subduction can bring two continental plates
together
* Less dense, buoyant continental lithosphere does not
subduct
*
Resulting
collision between two continental blocks produces highest mountain ranges on
land
e.g. ______________________________________
What was the Tethys Ocean and what happened to it?
______________________________ Plate Boundaries: (fig. 2.24)
•Plates
slide past one another and new lithosphere is neither created nor destroyed.
•Most
___________________ join two segments of a mid-ocean ridge along breaks in the
oceanic crust known as fracture zones.
•Some
cut through continental crust:
e.g. the
___________________ in California,
and the ____________________ in Turkey
Approximately ______% of the world’s active volcanoes are associated
with plate boundaries.
Most of the remaining active volcanoes are associated with
________________.
_______________
are thought to form by rising plumes
of mantle material
_______________ are:
- Long-lived structures
- Some
originate at great depth, perhaps at the mantle-core boundary
-
Volcanoes can form over them
e.g. ____________________
(fig. 5.37)
What is a hot spot track and how does it form?
How are satellite data being used to test the Plate
Tectonics Theory?
(fig. 2.29)
The basic driving force of Plate Tectonics is:
___________________________________________
Possible forces driving plate motion are: (fig. 2.30)
1) ______________________________
2) ______________________________
3) ______________________________
Proposed models for mantle convection include are: (fig.
2.31)
1) ______________________________
2) ______________________________
3) ______________________________
Why is the Plate
Tectonic Theory important?